Kruk Joanna, Czerniak Urszula
Faculty of Physical Culture and Health Promotion, University of Szczecin, Szczecin, Poland.
Asian Pac J Cancer Prev. 2013;14(7):3993-4003. doi: 10.7314/apjcp.2013.14.7.3993.
Scientific evidence for the primary prevention of cancer caused by physical activity of regular moderate-intensity or greater is rapidly accumulating in this field. About 300 epidemiologic studies on the association between physical activity and cancer risk have been conducted worldwide. The objectives of this paper were three-fold: (i) to describe briefly the components of physical activity and its quantification; (ii) to summarize the most important conclusions available from comprehensive reports, and reviews of the epidemiologic individual and intervention studies on a role physical activity in cancer prevention; (iii) to present proposed biological mechanisms accounting for effects of activity on cancer risk. The evidence of causal linked physical activity and cancer risk is found to be strong for colon cancer - convincing; weaker for postmenopausal breast and endometrium cancers - probable; and limited suggestive for premenopausal breast, lung, prostate, ovary, gastric and pancreatic cancers. The average risk reductions were reported to be 20-30%. The protective effects of physical activity on cancer risk are hypothesized to be through multiple interrelated pathways: decrease in adiposity, decrease in sexual and metabolic hormones, changes in biomarkers and insulin resistance, improvement of immune function, and reduction of inflammation. As there are several gaps in the literature for associations between activity and cancer risk, additional studies are needed. Future research should include studies dealing with limitations in precise estimates of physical activity and of a lack of consensus on what defines sedentary behavior of individuals and those linked with the proposed biomarkers to cancer risk and controlled exercise intervention trials.
在该领域，关于定期进行中等强度及以上体育活动对癌症一级预防的科学证据正在迅速积累。全球已开展了约300项关于体育活动与癌症风险关联的流行病学研究。本文的目的有三个：（i）简要描述体育活动的组成部分及其量化方法；（ii）总结综合报告以及关于体育活动在癌症预防中作用的流行病学个体研究和干预研究综述中得出的最重要结论；（iii）提出解释体育活动对癌症风险影响的生物学机制。研究发现，体育活动与结肠癌风险之间存在因果联系的证据很充分——令人信服；与绝经后乳腺癌和子宫内膜癌风险之间的联系较弱——有可能；与绝经前乳腺癌、肺癌、前列腺癌、卵巢癌、胃癌和胰腺癌风险之间的联系有限且具有提示性。据报道，平均风险降低20% - 30%。体育活动对癌症风险的保护作用被认为是通过多个相互关联的途径实现的：肥胖程度降低、性激素和代谢激素水平降低、生物标志物和胰岛素抵抗的变化、免疫功能改善以及炎症减轻。由于关于体育活动与癌症风险关联的文献存在若干空白，因此需要开展更多研究。未来的研究应包括解决体育活动精确估计方面的局限性以及对个体久坐行为定义缺乏共识的研究，以及与癌症风险相关的拟议生物标志物和对照运动干预试验的研究。
